When did Google announce its mobile-first indexing initiative and re-introduce the Mobile Friendly Testing Tool? By vmartinez When did Google announce its mobile-first indexing initiative and re-introduce the Mobile Friendly Testing Tool? December 2016 October 2016 November 2016 January 2017 Related content Related questions:To rank search listings, the Google algorithm…Your website is fast, secure, and mobile-friendly,…True or false? A mobile-friendly site automatically…What is the primary job of the Indexing service?